1. Field of the Invention
This invention relates to a piston having a coating on at least one piston land that deters the buildup of carbon. In particular, the invention relates to a piston that has a coating of hexagonal boron nitride (h-BN) on at least one of the piston lands or other areas of the piston.
2. The Prior Art
The buildup of carbon on piston lands, and in particular the top land of the piston, is a common problem, and can lead to degradation in the performance of the engine. This carbon buildup can also lead to wear on the piston liner, which leads to accelerated ring face wear and/or piston or ring scuffing. Additionally, if the land volume is partially or completely consumed by carbon, the dynamics of the piston rings can change, resulting in increased oil consumption for the engine.
Several attempts have been made to prevent such carbon build-up. For example, U.S. Pat. No. 8,020,530 to Taylor relates to piston having top land formed by a series of waves around the piston. Another method is to apply a coating to the piston, such as described in U.S. Pat. No. 7,383,806 to Abi-Akar et al. This coating is an electroless nickel PTFE coating.
It would be desirable to provide a way to prevent carbon buildup on piston lands and other parts of the piston that does not require altering the structure of the piston and which is simple and inexpensive to prepare.